I couldn’t put my finger on it at first but now it clicked:
the longest running thread by far (4.2k posts, the second longest has 395 posts) was “pet peeves” https://forum.xojo.com/t/pet-peeves/17053/4262 which was never shut down.
I have to ask: why not?
It certainly doesn’t help with Xojo, but it fits your criteria for being shut down.
The only difference I see: it isn’t critical of Xojo.
The same is true for a number of other threads that have no relevance but continue, while a LOT of posts that can be considered critical and links to other resources (even if Xojo-related) that allow criticism are removed and threads shut down.
So I’m having a hard time swallowing that “we only want to help you by shutting down threads” explanation.